1. Field of the invention
The present invention relates generally to an ear jack capable of preventing the generation of popup noise, and an electronic device including the same.
2. Description of the Prior Art
With the development of information communication technology and semiconductor technology, the spread and use of electronic devices are rapidly increasing. The recent electronic devices are not limited to their traditional unique areas, but are combined with various terminals. For example, a mobile communication terminal provides various functions such as a TV watching function (for example, mobile broadcasting such as Digital Multimedia Broadcasting (DMB) or Digital Video Broadcasting (DVB)), a music reproduction function (for example, MPEG Audio Layer-3 (MP3)), a picture photographing function, an Internet connection function, and a radio reception function, in addition to generation communication functions such as voice communication and transmission/reception of messages.
Further, the electronic device provides an earphone function for allowing a user to listen to audio and voice communications such that audio output is not exposed to the outside. Accordingly, the user may listen to music, broadcasts, recordings of voices, or voice communications using the earphone. Recent electronic devices may include an ear jack including a microphone terminal to provide a voice communication function or a voice recording function.
Generally, a standard ear jack may include a microphone terminal, a ground terminal, a right sound terminal, a left sound terminal, and a detection terminal. The standard ear jack may employ either a three-pole earphone or a four-pole earphone.
If the electronic device detects insertion of a three-pole earphone or a four-pole earphone through a detection terminal of the ear jack, it can recognize the type of an earphone connected through an output voltage of a microphone terminal. When it is recognized that a four-pole earphone including a microphone is connected to the electronic device, the electronic device may supply microphone bias power to the microphone terminal of the ear jack and may stop the supply of the microphone bias power when removal of the four-pole ear phone is detected. However, the microphone bias power is not interrupted instantaneously, but is slowly decreased over a predetermined period of time. This is because a capacitor having characteristics in which electric power is stored and slowly discharged is connected to the microphone terminal of the earjack.
In this way, a microphone terminal of the ear jack may contact the ground terminal of the four-pole earphone when the four-pole earphone is removed from the electronic device, according to the conventional art. Then, as the supply of the microphone bias power is not instantaneously interrupted, the microphone bias power is supplied to the ground terminal of the four-pole earphone, and the ground terminal of the earphone is released from the contact with the ground of the ear jack and is in an opened state. Accordingly, the microphone bias power supplied to the ground terminal of the earphone may be induced to the left sound terminal and/or the right sound terminal of the ear phone. In this case, in the electronic device, according to the conventional art, popup noise may be generated when the earphone is removed.